LONDON (Reuters) - If Crystal Palace avoid relegation from the Premier League this season, they can thank on-loan Liverpool defender Mamadou Sakho for playing a big part in their unlikely escape.

With their shock 2-1 victory at runaway league leaders Chelsea on Saturday, Palace have now won all four games since Sakho made his debut for the south Londoners in February, when they were firmly rooted in the drop zone.

Chelsea's goal, scored by Cesc Fabregas in the fifth minute, was the only one they have conceded in that four-game run.

Palace stand four points clear of Hull City, the highest placed team in the relegation spots, and Hull have played a game more.

After goals by Wilfried Zaha and Christian Benteke turned Saturday's game around with little more than 10 minutes on the clock, Sakho soaked up everything the hosts threw at him for the rest of it.

He cut out cross after cross and thwarted Chelsea striker Diego Costa who showed his frustration with a late challenge on the France defender to earn himself a yellow card.

Sakho's performance was all the more impressive as his starting partner in central defence, James Tomkins, was substituted for an injury at halftime, only for Tomkins' replacement Scott Dann to be taken off on a stretcher early in the second half.

Palace coach Sam Allardyce said the arrival of Sakho two months ago had given the team a resilience that was sorely lacking when he took over the struggling side in late December.

"He's leading, he's talking to players, he's taking a commanding role both in his performance and his information that he is giving out on the field, and of course that has helped tremendously in our defensive resilience," he told reporters.

"Having only conceded one goal in the last four games shows how important he is for us and what effect he has had on the team," Allardyce said.

Sakho fell out of favour at Liverpool last year when he was dropped from the first team and was sent home from a pre-season tour of the United States for disciplinary reasons.

He was suspended in April by UEFA for failing a drugs test, although the case was dropped by European soccer's governing body after his lawyers argued that a fat-burner used by the player was not on the list of banned substances.

On Saturday, Sakho said Palace's battling spirit could help them avoid relegation. "It's a good team with good players and we are starting to believe," he told BBC radio. "If you fight always like it's your last day, you can reverse everything."

Palace still have a lot to do to ensure their survival in the top flight. Allardyce has said they face the most difficult set of fixtures among the relegation candidates. And the injuries to Tomkins and Dann make the challenge all the harder.